Conventionally, as an apparatus of this type, touch panels of various methods have been proposed or are commercially available. Such touch panels are prevalently used since they allow easy operation of a personal computer (PC) on the screen without using any special tool or the like.
Various methods such as a method using a resistor membrane or an ultrasonic wave, and the like are available. As an apparatus using light, as disclosed in Japanese Patent Laid-Open Nos. 2001-84107, 2003-186616, and the like, there are provided apparatuses which detect the angle of a region which is shielded by a finger or the like in the input region, and detect the coordinates of the light-shielded position, i.e., input position in the arrangement in which a recurrent reflector is arranged around a coordinate input region, light coming from photo transmission means is reflected by the recurrent reflector, and a light amount distribution is detected by photo reception means.
These apparatuses aim at providing a coordinate input apparatus that allow a plurality of operators to make inputs. For example, Japanese Patent Laid-Open No. 2001-84107 describes the following contents. That is, an apparatus has angle detectors each of which cyclically detects a point designated on an input region by pointing means as an angle, and comprises an angle memory for storing an angle detected in the previous cycle, an angle selector for, when the number of detected angles in the current detection is larger than that in the previous detection, selecting an angle closest to the angle stored in the angle memory from the angles detected in the current detection, and a coordinate calculator for detecting coordinates on the basis of the selected angle. When the number of currently detected angles is larger by one than the number of previous detected angles for each angle detector, coordinates input by another pointing means are detected from the angle which is not selected by the angle selector. This apparatus also has identifier assignment means which can assign an identifier of the pointing means to coordinates to be output. When coordinates are to be output to a computer or the like, two coordinate positions designated by two pointing means can be identified from each other.
Japanese Patent Laid-Open No. 2003-186616 describes the following contents. That is, when two predetermined objects are simultaneously inserted onto an information input region, four two-dimensional position coordinate values are calculated except for a special case. The angles of light beams coming from photo transmission means, which are shielded or reflected by the predetermined objects that pointed the information input region, are calculated, and two two-dimensional position coordinate values actually pointed by the two predetermined objects are determined from the four calculated two-dimensional position coordinate values on the basis of the calculated angles. Furthermore, the arrangement has means for assigning different identification numbers to the two-dimensional position coordinate values calculated first. It is determined to which of the previously calculated two-dimensional position coordinate values each of the two two-dimensional position coordinate values which are kept calculated is closer, and the identification number of the previously calculated two-dimensional position coordinate value which is determined to be closer is kept assigned.
In the aforementioned apparatus, the pointing means is a finger or a pen-shaped pointing device. The coordinate input apparatus of this type is configured to control an application by pointing (touching) the screen. The pen which forms the above apparatus cannot transmit any commands for controlling a computer by itself, and has many restrictions upon operation of an application on the computer, thus causing problems in terms of functions. Hence, such pointing means is not always convenient.
On the other hand, upon operation of an application on the computer, functions corresponding to left clicking, right clicking, and the like as mouse functions are indispensable. An apparatus that allows various operations depending on how to touch so as to implement these functions is known. For example, this apparatus implements functions by so-called gesture input operations or the like by means of touch intervals and input traces. However, it is troublesome for the operator if he or she must learn gesture commands, and cannot operate intuitively. Hence, the operability is not so good as in the above case.
In order to allow inputs by a plurality of operators, attributes corresponding in number to input pointing means must be appended to coordinate values to be output to the computer side when the coordinate values are output. More specifically, in order to display the coordinate values input by each pointing means as a continuous input trace for that pointing means, the computer must recognize the pointing device that input the coordinate values.
As the apparatus corresponding to the above description, each of Japanese Patent Laid-Open Nos. 2001-84107 and 2003-186616 described above discloses the arrangement of a coordinate input apparatus which allows inputs by a plurality of operators. As identification numbers to be assigned to coordinate values input by the plurality of operators, different identification numbers are assigned in turn to those which are input earlier, and the same identification numbers are kept assigned to coordinate values which have closer distances to immediately preceding coordinate values. The identification number is kept assigned to the coordinate values of each pointing device until all inputs disappear.
However, with this arrangement, while the continuity of the trace after input can be assured, the attribute of the coordinate value input first cannot be determined.
Therefore, it is impossible to assign the attribute of the pen itself to the coordinate values to be output. A trace can be drawn during continuous input. However, since the identification number is cleared once the touch operation is completed, the functions of an application cannot be fully used. For example, problems are posed in operations when the operator wants to change a mode by pressing once an icon used to change a color, thickness, graphic, or the like as an operation for changing the line type or shape of drawing during input. That is, inputs using a plurality of pens are allowed, but combinations of pointing devices used to input and commands cannot be determined. Hence, processes corresponding to the attributes of pointing devices cannot be done.
Therefore, in order to use an application on the computer by a plurality of operators with high operability, unique attributes of pointing devices of the operators must be assigned to a plurality of input coordinate values.